Room-temperature NH3 gas sensor based on Ag-PPy core-shell nanowires

A novel room-temperature NH3 gas sensor leveraging Ag-polypyrrole (Ag-PPy) core-shell (C-S) nanowires (NWs) was fabricated via a one-pot redox polymerization method based on the common-ion adsorption effect. The compositional and microstructural characteristics of the Ag-PPy C-S NW film were systematically analyzed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The PPy shell thickness and the Ag core diameter in the synthesized Ag-PPy C-S NWs were approximately 31.2 nm and 47.7 nm, respectively, while the nanowire lengths ranged from 5 to 10 mu m. The NH3 gas sensor based on Ag-PPy C-S NWs exhibited a response 2.65 times higher than that of pristine PPy NWs when exposed to 5 ppm NH3 at room temperature. This enhanced performance was related to the synergistic effects of the metal-semiconductor (MS) interface within the C-S structure and the efficient charge carrier transport provided by the Ag NW architecture. The Ag-PPy C-S NW-based NH3 gas sensors demonstrated exceptional performance, including high sensitivity to low NH3 concentrations, rapid response times, strong selectivity, excellent reproducibility, a low detection limit, and long-term stability under ambient conditions. These attributes highlight their potential for enabling low power consumption and economical NH3 gas sensors for practical applications.